The present invention relates to a cleaning sheet which is particularly applied to an imaging system employing a photo-pressure sensitive sheet coated with microcapsules.
An imaging system conventionally employing a photo-pressure sensitive sheet containing microcapsules encapsulated with a chromogenic material and a photo-sensitive material such as a photo-curable material has been proposed and developed. The transfer imaging system works such that a sheet coated with encapsulates of a chromogenic material and a photo-curable material is exposed based on the image-wise information to an exposure means so that the microcapsules on the sheet are cured in the exposed area. Then a transfer sheet is pressed face to face against the photo-pressure sensitive sheet with pressure rollers, so that the unexposed, i.e., non-cured microcapsules are ruptured, and the effused encapsulated chromogenic material reacts with a developer on the transfer sheet, thereby forming an image. This system is depicted in U.S. Pat. No. 4,399,209. However, this transfer imaging system has a defect that the photo-curable material from the ruptured microcapsules occasionally leaks out from the edge of the photo-pressure sensitive sheet, which is pressed together with the transfer sheet, and sticks to the surface of the pressure roller. This leakage onto the pressure member results in an uneven surface thereof, which has tiny bumps thereon, resulting in that the pressure roller does not press the photo-pressure sensitive sheet and the transfer sheet together uniformly, thus reducing the quality of the final image. In order to remove such leakage of the photo-curable material, a brush, a blade, or such are devised to run along the roller in contact therewith while wiping up the leaked material. However, this mechanical removal does not clean the surface of the roller sufficiently, so problem of nonuniform pressure on the sheets remains, resulting in a blemished image.